Occlusive cuff

• US 4,770,175 A
• Filed: 10/22/1986
• Issued: 09/13/1988
• Est. Priority Date: 10/22/1986
• Status: Expired due to Term

• Current Assignee: Zimmer Orthopaedic Surgical Products (Zimmer Biomet Holdings, Inc.)
• Original Assignee: Western Clinical Engineering Ltd.
• Inventors: McEwen, James A.
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): Kartchner, Gene B.
• Application Number:
  US06/921,461
• Time in Patent Office: 692 Days
• Field of Search: 128/327, 128/679, 128/686, 128/672, 128/677
• US Class Current: 606/203
• CPC Class Codes: A61B 17/1355 Automated control means therefor
• CPC Class Codes: A61H 2201/5074 using electric pressure transducers with proportional output

Abstract

An occlusive cuff which is useful for safety occluding blood flow into the digit of a human subject distal to the cuff for the duration of a surgical procedure. The cuff comprises: an inflatable, readily collapsible tube formed of thin, flexible and substantially inextensible material wherein the ratio of the tube width to digit circumference is substantially smaller than the fixed ratio of tube width to digit circumference specified for a sphygmomanometer cuff which would accurately estimate blood pressure in the digit; means for securing the tube around substantially all of a portion of the digit; pressurizing means for pressurizing the tube; pressure relief means for depressurizing the tube; pressure sensing means for producing a cuff pressure output signal representative of the pressure to which the tube is pressurized; occlusion pressure selection means for selecting remotely the minimum constant pressure to which the tube should be pressurized to safety occlude blood flow into the digit distal to the cuff; pressure regulator means responsive to the cuff pressure output signal for selectably activating the pressurizing means and the pressure relief means to maintain the cuff pressure near the selected pressure over a time period suitably long for the performance of a surgical procedure.

Claims

1. An occlusive cuff for safely occluding blood flow into a portion of a limb as small as a single, isolated digit to facilitate surgery on the limb portion, comprising in combination:

(a) a pressurizable, substantially inextensible tube having a length sufficient for encircling a limb at a selected location, and having a width wherein the ratio of tube width to limb circumference at the selected location is substantially different than the ratio of bladder width to limb circumference required in a sphygmomanometer cuff for accurate estimation of blood pressure at the selected location;

(b) means for snugly encircling the limb with the tube at the selected location in a manner that does not allow the tube to contact the limb distal to the selected location, and so that the tube contacts the limb around substantially all of its circumference without overlapping around the limb;

(c) tube-securing means for securing the tube so that the tube remains snugly around the limb at the selected location while the tube is pressurized to a level sufficient to occlude blood flow in the limb encircled by the tube;

(d) occlusion pressure selection means for selecting remotely the minimum constant pressure to which the tube should be pressurized to occlude blood flow in the limb, wherein the occlusion pressure selection means comprises pressure graduations marked on the tube so that a pressure graduation corresponding to the selected pressure is visually identifiable when the cuff is secured snugly around the limb at the selected location, and wherein each pressure graduation is an estimate of the minimum constant pressure in the tube which will normally occlude blood flow over a time period suitably long for the performance of a surgical procedure when the cuff is secured snugly around a normal limb of predetermined circumference in a normotensive subject.

2. An occlusive cuff for safely occluding blood flow into a portion of a limb as small as a single, isolated digit to facilitate surgery, comprising in combination:

(a) an inflatable, readily collapsible tube of thin, flexible and substantially inextensible material having a length sufficient to encircle the limb, wherein the ratio of tube width to the circumference of the limb is substantially different than the ratio of tube width to limb circumference required in a sphygmomanometer cuff for accurate estimation of blood pressure in the limb;

(b) tube-securing means for securing the tube around a limb having any circumference within a predefined range in a manner such that the tube substantially encircles the limb without overlapping on itself around the limb;

(c) a retaining strap for wrapping around the outer surface of the collapsed tube encircling the limb to direct inflation inwardly when the tube is pressurized; and

(d) strap-securing means for securing the strap around the outer surface of the tube as it encircles the limb wherein the strap-securing means secures the strap independently of the tube-securing means such that the tube remains encircling the limb if either the tube-securing means or the strap-securing means becomes ineffective.

3. An occlusive cuff for safely occluding blood flow into a portion of a limb as small as a single, isolated digit to facilitate surgery, comprisintg in combination:

(a) an inflatable, readily collapsible tube of thin, flexible and substantially inextensible material having a length sufficient to encircle the limb, wherein the ratio of tube to the circumference of the limb is substantially different than the ratio of the tube width to limb circumference required in a sphygmomanometer cuff for accurate estimation of blood pressure in the limb;

(b) tube-securing means for securing the tube around a limb having any circumference within a predefined range in a manner such that the tube substantially encircles the limb without overlapping on itself around the limb;

(c) pressurizing means coupled to one end of the tube for supplying gas near a selected pressure to the tube for the duration of a surgical procedure; and

(d) pressure sensing means for producing an indication representative of the pressure of gas in the tube for the duration of a surgical procedure, wherein the pressure sensing means is coupled to the opposite end of the tube such that there must be an opening in the tube around substantially all of the circumference of the limb encircled by the tube for the pressure sensing means to indicate the pressure of the gas supplied by the pressurizing means.

4. An occlusive cuff as defined in claim 3 wherein the tube-securing means includes means for enabling gas to flow within the portion of the tube in contact with the tube-securing means when the tube is secured around the limb.

6. An occlusive cuff as defined in claim 3 wherein the cuff pressure sensing means produces a cuff pressure signal representative of the pressure of gas in the tube and including:

(a) supply pressure sensing means for producing a supply pressure signal representative of the pressure of gas supplied to the tube, and

(b) pressure comparison means for producing a differential signal representative of the difference between the cuff pressure signal and the supply pressure signal.

7. An occlusive cuff as defined in claim 6 including alarm means for producing a blockage alarm when the differential signal exceeds a predetermined limit.

5. An occlusive cuff for safely occluding blood flow into a portion of a limb to facilitate surgery on the limb portion, comprising in combination:

(a) a pressurizable tube for positioning on a limb at a selected location;

(b) an occlusive band for encircling the limb and tube to secure the tube in position at the selected location on the limb and to direct inflation of the tube inwardly toward the limb when the tube is pressurized; and

(c) occlusion pressure selection means for selecting remotely a constant pressure to which the secured tube should be pressurized, wherein the occlusion pressure selection means comprises pressure graduations marked on a surface of the occlusive band in a manner such that the pressure graduation corresponding to the selected pressure is visually indentifiable when the occlusive band is secured snugly around the limb, and wherein each pressure graduation is an estimate of the minimum constant pressure normally required in the tube when the tube is secured snugly on a non-hypertrophied and non-atrophied limb of predetermined circumference in a normotensive subject to occlude blood flow into the limb distal to the location over a time period suitably long for the performance of a surgical procedure.

8. An occlusive cuff system for safely occluding blood flow into a portion of a limb as small as a single, isolated digit to facilitate surgery distal to the cuff, comprising in combination:

(a) an inflatable, readily collapsible and substantially inextensible tube for placing on the surface of a portion of a limb with the longitudinal axis of the tube parallel to the longitudinal axis of the limb portion;

(b) an occlusive band for encircling a portion of the limb onto which the tube has been placed longitudinally;

(c) first pressurizing means for causing pressure to be applied to the limb portion and segment of the tube beneath the occlusive band;

(d) second pressurizing means for causing fluid at a variable pressure to be coupled to one end of the tube;

(e) pressure-sensing means for producing a signal representative of the pressure of the second pressurizing means; and

(f) opening-pressure estimation means for varying the pressure of the second pressurizing means and for producing an opening pressure signal representative of the lowest pressure at which fluid passes from the end coupled to the second pressurizing means beneath the occlusive band to the other end of the tube.

9. An occlusive cuff system as defined in claim 8 including pressure-regulating means responsive to the opening pressure signal for regulating the first pressurizing means in a manner such that the opening pressure signal is maintained near a selected level.

10. An occlusive cuff system as defined in claim 8 wherein the width of the tube is sufficiently small relative to the circumference of the limb portion being encircled such that the tube conforms smoothly to the extremity beneath the occlusive band.

11. An occlusive cuff for encircling a digit and safely occluding blood flow into the digit of a human subject distal to the cuff for the duration of a surgical procedure, comprising in combination:

(a) a pressurizable, substantially inextensible tube having a length sufficient for encircling a digit at a selected location, and having a width wherein the ratio of the tube with to digit circumference at the selected location is substantially different than the ratio of bladder width to digit circumference required in a sphygmomanometer cuff for accurate estimation of blood pressure at the selected location;

(b) means for snugly encircling the digit with the tube at the selected location in a manner that does not allow the tube to contact the digit distal to the selected location, and so that the tube contacts the digit around substantially all of its circumference without overlapping around the digit;

(c) tube-securing means for securing the tube so that the tube remains snugly around the digit at the selected location while the tube is pressurized;

(d) pressurizing means for pressurizing the tube;

(e) pressure relief means for depressurizing the tube;

(f) pressure sensing means for producing a tube pressure output signal representative of the pressure to which the tube is pressurized;

(g) selectable reference signal means for producing any one of a number of constant signals, each representative of a predetermined constant reference pressure; and

(h) pressure regulator means responsive to the tube pressure output signal for selectably activating the pressurizing means and the pressure relief means to maintain the tube pressure near a selected pressure over a time period suitably long for the performance of a surgical procedure.

12. An occlusive cuff comprising:

(a) a pressurizing band for encircling the limb of a subject having predetermined blood pressure and for applying pressure to the limb, wherein the length of the outer surface of the encircling band does not change substantially as pressure is applied to the limb; and

(b) pressure graduations visible on the outer surface of the band for providing an estimate while pressure is not applied by the band of the minimum constant pressure which should normally be maintained by the band encircling the limb of the subject having predetermined blood pressure to occlude blood flow distal to the band for a desired time period.

13. An occlusive cuff system comprising:

(a) a pressurizing band for encircling the limb of a subject and for applying pressure to the limb;

(b) means for measuring the subject'"'"'s systolic blood pressure; and

(c) pressure graduations visible on the encircling band for indicating the level of the pressure applied by the band in relation to the subject'"'"'s measured systolic blood pressure so that the band occludes blood flow distal to the band.